Flotation processes are known in the art and are used for recovering and concentrating minerals from ores. In froth flotation processes the ore is crushed and wet ground to obtain a pulp. Additives such as mineral flotation or collecting agents, frothers, suppressants, stabilizers, etc. are added to the pulp to assist separating valuable materials from the undesired minerals or gangue portions of the ore in subsequent flotation steps. The pulp is then aerated to produce a froth at the surface. The minerals which adhere to the bubbles or froth are skimmed or otherwise removed and the mineral bearing froth is collected and further processed to obtain the desired minerals. Typical mineral flotation collectors include xanthates, amines, alkyl sulfates, arene sulfonates, dithiocarbamates, dithiophosphates and thiols.
U.S. Pat. No. 2,600,731 describes alkali metal salts of tertiary alkyl trithiocarbonates and processes to make same. The patent also describes the use of these compounds in ore flotation. Sodium diethyl dithiophosphate has also been described in other references as a collector in the separation of zinc and copper. The prior art has also described potassium ethyl xanthate and potassium isoamyl xanthate as ore flotation collectors for copper.
While the art of ore flotation has reached a significant degree of sophistication it is a continuing goal in the ore recovery industry to increase the productivity of ore flotation processes and above all to provide specific processes which are selective to one ore or to one metal over other ores or other metals, respectively, which are present in the treated material.